A vaulted ceiling follows the roof pitch with finishing materials applied to the rafters.
Soffit follows roof pitch.
To ensure proper ventilation calculate the correct number of soffit vents for your home.
Rake boards follow or parallel your roof pitch.
And in many of these cases the hip roof forms a large volumetric attic space to ventilate.
They are generally made of two by four lumber and are used to form the pitch of a roof.
Drawing a superimposes the common rafters for the two roof pitches and illustrates the problem that occurs when roof layout starts at the outside edge of the exterior walls.
For projects involving vents with motors the calculation formula is different.
Another by product of this roof configuration is varying soffit heights and widths which require further design decisions.
For example six inches up for every 12 inches across.
Of course there should be intake vents to ensure a balanced system.
That first number is what changes but stays within a range.
This ceiling can make a porch feel larger add drama to the space and keep your porch cool in hotter climates.
In this article we stick to the basics which follows this logic.
The most common parameter is to maintain an equal ridge height over building sections with differing spans.
Rakes are always miter joined at the ridge of your roof.
2 12 pitch or lower low slope or nearly flat.
11 12 roof pitch and higher increase the amount of ventilation by 30 percent.
Here s a rule of thumb to follow.
There s no correct way to finish rake lower edges.
To maintain a consistant ridge height in these situations the roof pitch must be adjusted.
You measure this as a rise and run equation such as 6 12 where the rake angle rises six units in 12 units of run.
Where roofs of unequal pitch join it requires careful layout to create equalwidth soffits with equal height fascias.
Figure 7 mechanical ventilation used with a hip roof.
Rafter roof rafters are one of the most important parts of any type of roof.
The calculated soffit drop is the measurement from top of wall vertically down to the underside of soffit sheeting.
They come from each side of the roof and meet in the middle to form what looks like a v.
Up to 6 12 roof pitch use the standard formula as explained in this article.
When a pitch value is shown it will appear as 2 12 which would indicate a nearly flat roof or 18 12 very steep.
The second number run is always going to be 12.
One method is to use a powered attic vent with a humidistat thermostat located close to the ridge or top of the roof.
